Dual role of the serine protease homolog BmSPH-1 in the development and immunity of the silkworm Bombyx mori. (August 2018)

• Record Type: Journal Article
• Authors: Lee, Kwang Sik; Kim, Bo Yeon; Choo, Young Moo; Jin, Byung Rae
• Is Part Of: Developmental and comparative immunology. Volume 85(2018)
• Page Start: 170
• Page End: 176
• Publication Date: 2018-08
• Subjects: Bombyx mori -- Development -- Immunity -- Serine protease homolog -- Silkworm; Immunology -- Periodicals; Developmental immunology -- Periodicals; 616.079
• DOI: 10.1016/j.dci.2018.04.011
• Languages: English
• ISSNs: 0145-305X

Abstract

Abstract: Serine proteases and serine protease homologs are involved in the prophenoloxidase (proPO)-activating system leading to melanization. The Bombyx mori serine protease homolog BmSPH-1 regulates nodule melanization. Here, we show the dual role of BmSPH-1 in the development and immunity of B. mori . BmSPH-1 was expressed in hemocytes after molting and during the larval-pupal transformation in normal development. In contrast, following infection, BmSPH-1 was expressed in hemocytes and cleaved in the hemolymph, which resulted in the induction of PO activity. Moreover, BmSPH-1 was cleaved in the cuticle during the larval-pupal transformation and early pupal stages. In BmSPH-1 RNAi-treated silkworms, the reduced BmSPH-1 mRNA levels during the spinning stage or the prepupal stage resulted in the arrest of pupation or pupal cuticular melanization, respectively. The binding assays revealed that BmSPH-1 interacts with B. mori immulectin, proPO, and proPO-activating enzyme. Our findings demonstrate that BmSPH-1 paticipates larval-pupal transformation, pupal cuticular melanization and innate immunity of silkworms, illustrating the dual role of BmSPH-1 in development and immunity. Highlights: Bombyx mori serine protease homolog BmSPH-1 functions in both development and immunity. BmSPH-1 acts in the immune response during infection. BmSPH-1 is required for pupation during the larval-pupal transformation. BmSPH-1 participates in pupal cuticular melanization. BmSPH-1 interacts with BmIML, BmPPAE, and BmPPOs.